The present invention relates to a pressure clamp adapter for mounting a thermistor on an existing thermostat control support bracket.
Thermostat control devices for electric water heaters have been mounted for many years on support brackets which are attached to the spuds secured to the tank of the water heater. An example of such a support bracket is described in U.S. Pat. No. 4,399,971. These spuds provide for the removable connection of the resistive heating elements. The support bracket is formed from spring steel material and has a spud connecting aperture and a pair of upstanding spring arms each having a bight formation at an outer end for clamping a support of the thermostat control device against the water tank. The thermostat control device is mounted on the support and in close proximity to the tank outer wall whereby to sense the temperature in that region. A mechanical potentiometer is provided on the control thermostat device to manually set the operating parameters of the resistive element to control the temperature of the water inside the tank in the area of the thermostat. Because such thermostat control devices are not in direct contact with the wall of the water tank there exists a gap between the temperature sensor of the thermostat control device and the actual temperature of the water inside the tank in the vicinity of the thermostat.
With the advent of automatic controls, a single electronic controller device is now utilized to control the operation of the resistive heating elements, being two or more of the resistive elements mounted at different levels in the water tank. Temperature sensor are required to be attached to the tank outer wall to sense the temperature of the tank wall at precise locations.
Because there are hundreds of thousands of electric water heaters on the market with existing thermostat control devices and their support brackets, when it is required to convert these to automatic controllers, there becomes a need to attach thermistors to the tank outer wall to feed temperature signals to the controller. Thermistors are resistors of small dimensions whose resistance varies with temperature. They also carry two leads to provide resistance readings to control circuitry of the controller. These thermistors may have sizes in the range of one eight to one quarter on an inch by a length of about half inch and have different shapes. There is therefore a need to inexpensively replace the thermostat control device and their support and secure thermistors to the tank outer wall and rewire to connect the thermistors to the controller secured outside the water heater for ease of access thereto.